The present invention relates generally to telecommunications systems for providing data and voice communications and, in particular, to a line card and method which supports POTS and asymmetric DSL and which supports DSL.
There is an ever pressing need for telecommunication service providers to provide cheaper, faster and more robust high speed data communications to consumers. To complicate matters for service providers, there are many different high speed data communication services being used by subscribers. For example, integrated services digital network (ISDN) services, digital subscriber line (DSL) services and European periodic pulse metering (PPM), or Teletax, services, are some of the current methods commonly used to transmit data.
To further complicate matters, many of these methods are subdivided into different types. For example, the DSL family of high speed data communications consists of a host of various services, which are typically designated as xDSL where “x” represents one of the family of DSL services. Current xDSL services include Asymmetric DSL (ADSL), Rate adaptive DSL (RADSL), High bit rate DSL (HDSL), Very high speed DSL (VDSL) and symmetric DSL (SDSL), HDSL2 and SHDSL. As is known in the art, HDSL operates over two twisted cable pairs, while HDSL2 operates over a single twisted cable pair. For further details of providing xDSL services and systems for providing these services, the reader is directed to U.S. Pat. No. 6,144,659, entitled “Telecommunications Equipment Support of High Speed Data Services”, issued on Nov. 7, 2000 to Nye and Posthuma and U.S. patent application Ser. No. 09/258,879, entitled “Telecommunication Equipment Support of ISDN Communication Lines for High Speed Data Transmission”, filed on Feb. 25, 1999 by Posthuma, the disclosures of which are hereby incorporated by reference.
In addition, a large percentage of consumers still use plain old telephone service (POTS) lines for data communications. Therefore, the telecommunications systems of the service providers need to support a wide variety of telecommunications services. Currently, telecommunications systems would, for example, incorporate separate circuits and devices for the separate services.
In particular, current xDSL line cards are directed to either symmetric or asymmetric applications. As those skilled in the art will readily comprehend, “symmetric” and “asymmetric” refer to the bandwidth in each direction of the communication. If the bandwidths are substantially equal in both directions, the service is termed “symmetric”. If the bandwidths are not equal, the service is termed “asymmetric”.
Line cards, for example, supporting symmetric applications for such xDSL, technologies as HDSL2 and SDSL have not supported concurrent operation with POTS. Line cards are known which provide concurrent asymmetric xDSL services, such as ADSL or ADSL Lite, and POTS. Unfortunately, those line cards do not support symmetric xDSL services. Hence, different circuit packs, or line cards, are needed in the telecommunications systems for the various symmetric and asymmetric services and POTS.
Accordingly, there is thus a need in the art for a line card and method for supporting concomitant operation of POTS and asymmetric digital subscriber line services and for supporting symmetric and asymmetric digital subscriber line services.